Why I did it
Fix typo and missing files in SN3800 and SN4600C's buffer templates
How I did it
ingress_lossless_xoff_size => ingress_lossless_pool_xoff add missing files for SN4600C-D100C12S2
How to verify it
Deploy the fix and verify whether the device can be up.
Signed-off-by: Stephen Sun <stephens@nvidia.com>
